If the goal is to practice- you don't need anything really. If the goal is to jam, you have many options. You might be able to find a headphone OUT, or if not, you can simply add a mixer and/or some studio monitors.

IMO, the best option for you, playing quietly at home (I am in the same boat), is to buy some Neural DSP plug-in's (amazing quality- #1 in my book by far, and I've tried many.) I bought 2 of their plug-ins and they seem to cover a lot of tones. Nice, clean visual on screen interface as well. If you go this route, you will also need an audio interface like a UMC204HD (works great for me.) It gives you full control over of the volume and a headphones and lets you to play your guitar using the software in your computer. It works great- also lends itself to recording very nicely.